Answer: inspiration involves muscular contractions and expiration is passive.
Explanation: Quiet breathing can be defined as a process of moving air into and out of the lungs to facilitate gas exchange with the internal environment that occurs at rest and does not require the cognitive thought of the individual. Here, expiration employs only the elastic recoil of the lungs. Inspiration involves muscular contractions (the diaphragm contracts, causing the diaphragm to flatten and drop towards the abdominal cavity).
